The embodiments described herein relate generally to image processing, and more particularly, to detecting objects in a continuous stream of items from imaging data generated by a computed tomography (CT) imaging system.
Known checkpoint scanning systems, such as Advanced Technology X-ray (AT) systems or Threat Image Projection Ready X-ray (TRX) systems, are designed to scan a continuous stream of luggage and other objects to provide adequate throughput for travelers at an airport checkpoint, for example. However, it is common for an operator of a checkpoint scanning system to start and stop the flow of items for a number of reasons, such as to further inspect a suspicious piece of luggage or a passenger holds up a security line, for example. This is not an issue for AT and TRX systems because of the nature of the technology used to acquire image data. In contrast, for CT scanning systems this starting and stopping during image data acquisition is an issue. It causes the reconstruction process to become much more computationally intensive relative to the reconstruction process associated with image data being acquired at a constant velocity and pitch.
Thus, reconstructing images from data acquired during periods of acceleration and deceleration where the pitch is continually changing remains daunting. To attempt to cope with reconstruction processing during the starting and the stopping using conventional techniques a relatively powerful computer would be required to handle the computational complexity of a variable pitch in a reasonable amount of time. However, these more powerful computers remain prohibitively expensive for a security checkpoint application. When a traditional computer is utilized to process the complex computations of a variable pitch that occur during the starting and stopping of the continuous stream of items, the excessive amount of time required to reconstruct CT images remains impractical for the high passenger throughput needed at a checkpoint, for example.